Polymer dispersions using hydrocarbons and graft copolymer dispersing agents



United States Patent C) 3,232,903 POLYMER DISPERSIONS USING HYDROCARBONS AND GRAFT COPOLYMER DISPERSING AGENTS Claude J. Schmidle, and George L. Brown, Moorestown,

N.J., assignors to Rohm & Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Filed Oct. 19, 1961, Ser. No. 146,315

" 3 Claims. (Cl. 26033.6)

This application is a continuation-in-part of our copending application Serial No. 758,892, filed September 4, 1958.

The present invention is concerned with the production of dispersions of polymers within organic liquid media in which the polymers are relatively insoluble and it is particularly concerned with polymer dispersions in hydrocarbon liquids. The invention is concerned with a polymerization technique in which the monomers are polymerized within organic liquids in which the polymer obtained is relatively insoluble, the polymerization being effected in the presence of a dispersing agent for maintaining the polymer produced as discrete particles in dispersed condition within the polymerization medium.

It is an object of the present invention to provide dispersions of synthetic addition polymers in organic liquid media using essentially hydrophobic dispersing agents for maintaining the insoluble polymer particles dispersed in the system in substantially stable form. It is another object of the invention to provide a polymerization system adapted to be varied widely in respect to viscosity characteristics merely by the choice of solvent or one or more components thereof. Another object of the present invention is to provide a polymer dispersion in organic liquids comprising discrete particles of the polymer which are insoluble in the liquid but dispersed therein by means of a substantially hydrophobic dispersing agent whereby films, coatings, and impregnations obtained from the dispersions are of quite hydrophobic character and consequently resistant to moisture. Another object of the invention is to provide a polymerizationsystem of essentially inert, non-aqueous or anhydrous type which, because of its non-aqueous quality, is adapted to the production of dispersed polymer systems in which the polymer is of crystalline character. Another object of the invention is to provide a polymerization system which is adapted to produce dispersions of discrete insoluble particles within organic solvents using monomers which because of their reactive character are incapable of polymerization in aqueous systems.

Another object of the invention is to provide a polymerization system in a non-aqueous medium or vehicle whereby, because of the non-aqueous character, a wider variety of polymerization techniques may be employed in the production of the polymer. Thus, in the polymerization systems of the present invention, the polymerization may be elfected not only by the use of free-radical initiators but also by anionic and cationic techniques which latter two techniques cannot be performed in an aqueous system. Another object of the invention is to provide for the preparation of water-soluble polymers in an anhydrous medium. Other objects and advantages of the invention will be apparent from the description thereof hereinafter.

In accordance with the present invention, polymerizable and copolymerizable ethylenically unsaturated monomers having at least one group of the formula CHFO: are polymerized to form addition polymers of either linear or cross-linked type in a hydrocarbon solvent medium containing a dispersing agent of polymeric character which is also of essentially hydrophobic nature. The dispersing agent may be formed in situ inthe polymerization medium or it may be formed before it is introduced into the 3,232,903 Patented Feb. 1, 1966 polymerization medium in which the main polymer is to be prepared.

Liquids that may be used in the polymerization system of the present invention include any liquid hydrocarbon whether formed of a single compound or of a mixture of compounds. The hydrocarbon may be of aliphatic character, either acyclic or alicyclic, aromatic, or naphthenic, or the polymerization medium may be made up of a mixture of these various types of hydrocarbons. Examples of individual hydrocarbons that may be employed include pentane, n-hexane, cyclohexane, n-heptane, n-octane, isooctane, benzene, toluene, xylene (0-, m-, or p-xylene). Commercially-available hydrocarbon mixtures may be employed such as mineral spirits, gasoline, xylene mixtures, solvent naphthas of aromatic, aliphatic, or naphthenic character, alkyl benzenes in which the alkyl group or groups have from 1 to 4 carbon atoms, octane fractions which contain a mixture of octane isomers, and so on. Generally, it is preferred to employ a hydrocarbon liquid medium comprising at least 50% by weight of nonaromatic components, and especially those of aliphatic or paraflinic makeup. This preference has the advantage of lower cost and capacity to disperse a wider variety of polymers in the form of discrete particles.

It is essential that the hydrocarbon be of liquid character, but it may have a wide boiling range from a minimum of about -50 C. (in which case high pressures may be needed in the polymerization) to a maximum which may be as high as 300 C. For most purposes, the boiling point should be from about 0 C. up to about 200 C. The boiling point or boiling range of the liquid hydrocarbon system may be chosen as desired to be suitable for the particular operation in which the polymer dispersion prepared in the hydrocarbon is to be used. Thus, in coating or impregnating operations intended to be carried out in low temperature climates, a liquid hydrocarbon medium having a relatively low boiling point such as from about 30 to 35 C. may be preferred. A similar boiling point range may be selected for pressure systems, as in aerosol sprays. On the other hand, where the coating and impregnating operation is to be carried out in the equipment provided with relatively high temperature drying ovens or rolls, the hydrocarbon system may have extremely high boiling points such as from 275 to 300 C. However, for most purposes, it is preferred to employ liquids boiling in the range from about 50 C. to about 235 C.

It is essential to select the hydrocarbon with the particular polymer to be prepared therein in mind. The hydrocarbon medium should be such that the polymer formed is relatively insoluble therein. This does not preclude the use of a hydrocarbon medium capable of swelling the polymer or of dissolving in the polymer up to 1% or even 50% on the weight of the polymer. A small proportion up to 10% of the polymer prepared may be of low molecular weight and soluble in the hydrocarbon medium. When the polymer prepared in the system has an appreciable solubility within the hydrocarbon medium, that portion which dissolves serves to thicken the system. By employing a composite hydrocarbon medium in which one of the components exerts a solvent action on the polymer and the other is substantially completely inert, controlled viscosity can be obtained merely by adjusting the proportions of the two components of the mixture. For example, a mixture of octane and toluene may be employed for the preparation of a dispersion of a polymer which has complete solubility in toluene and substantially no solubility in octane. By increasing or decreasing the proportion of toluene in the system, the viscosity in the system may be varied as desired from a very high value down to a very low value approaching that of the liquid used for the vehicle. In all of the systems of the present invention, the largest portion of the polymer, at least 90% by weight thereof, remains in undissolved condition dispersed in the system as discrete particles having sizes of 10 microns or less, and preferably from about 0.1 to 2 microns, by a dispersant more particularly described hereinafter.

The essentially hydrophobic dispersing agents employed in the systems of the present invention are of polymeric character. The polymeric dispersing agent contains in its molecule two essentially different portions or components, one of which is preferentially soluble in, or miscible with, the hydrocarbon medium at least to that degree which would result in the formation of a colloidal solution thereof, which portion may or may not be incompatible with the polymer to be dispersed which may be termed the main or primary polymer in the system. The other component or portion of the polymeric dispersing agent molecule is preferentially soluble in, or miscible with, the main polymer which portion may or may not be incompatible with the hydrocarbon medium. Thus, the first-mentioned portion has a stronger afiinity for the hydrocarbon medium than the other whereas the second- :mentioned portion has a stronger affinity for the main polymer. The second-mentioned component of the dispersant may be introduced into the polymeric dispersing agent molecule by a grafting operation wherein there is used a monomer which is of the same chemical constitution, or of sufficiently similar chemical constitution, as that of the monomer or monomers employed in the formation of the main polymer so that the portion of the dispersing agent molecule derived therefrom is compatible or miscible with the main or primary polymer.

The formation of the dispersing agent may be effected in situ simultaneously with the main polymerization. Alternatively, the dispersing agent may be formed by 21 separate preliminary graft polymerization and then introduced into the main polymerization system.

The polymeric precursors adapted to form the polymeric dispersing agents include hydrocarbon-soluble acrylic polymers and various modified or oxidized vegetable oils.

Among the synthetic linear polymers of acrylic type that may be employed as the precursors are the oil-soluble types of polymeric esters of acrylic acid or methacrylic acid such as copolymers of esters of methacrylic acid or acrylic acid formed with alcohols having 4 to 18 carbon atoms or of mixtures of such esters with esters of methacrylic acid or acrylic acid formed with alcohols having 1 to 5 carbon atoms, wherein suflicient hydrocarbon groups of at least four carbon atoms are present to impart solubility of the precursor in the solvent medium used in the polymerization system. Mixtures of methacrylate and acrylate esters can be used in the production of the solvent-soluble precursors. Such polymeric precursors may also include in the copolymer molecule substantial proportions from 1% to as much as 50% by weight of units derived from other monoethylenically unsaturated monomers such as maleic anhydride, acrylic acid, methacrylic acid, vinyl pyrrolidone, N-dimethyla-minoethyl acrylate or methacrylate, N,N-dirnethylaminoethyl acrylamide or methacrylamide, dimethylaminoethyl vinyl ether, dimethylaminoethyl vinyl sulfide, ureidoalkyl vinyl ether or sulfide such as the ureidoethyl vinyl ether or sulfide, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, vinyl laurate, vinyl stearate, vinyl oleate, ethylene, isobutylene, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, vinyl ethyl ether, vinyl isobutyl ether.

As the precursor for the polymeric dispersing agents, oxidized vegetable oils such as blown linseed oil, blown .castor oil, and the like may be employed.

In general, the molecular weight of the dispersing agent may be of a wide range, but preferably it is from one-tenth to ten times that of the main polymer.

The monomers which are adapted to be converted into dispersed polymers by the polymerization system of the present invention may be selected from a wide variety such as the vinyl esters of fatty acids having from 1 to 18 carbon atoms including vinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate, vinyl oleate, and vinyl stearate. Esters of acrylic acid or of methacrylic acid with alcohols having from 1 to 18 carbon atoms may likewise be employed. Examples include methyl acrylate or meth acrylate, ethyl acrylate or methacrylate, propyl acrylate or methacrylate, isopropyl acrylate or methacrylate, the various butyl acrylates or methacrylates, cyclohexyl acrylate or methacrylate, benzyl acrylate or methacrylate, phenyl acrylate or methacrylate, n-hexyl, n-octyl, t-octyl, dodecyl, hexadecyl, or octadeoyl acrylates or methacrylates. Acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, styrene, a-methyl styrene, vinyl toluenes, acrylic acid, acrylic acid anhydride, methacrylic acid, methacrylic acid anhydride, maleic anhydride, furnaric acid, crotonic acid, allyl acetate, glycidyl methacrylate, t-butylaminoethyl methacrylate, hydroxyalkyl acrylates or methacrylates such as fi-hydroxyethyl methacrylate, B-hydroxyethyl vinyl ether, fi-hydroxyethyl vinyl sulfide, vinyl pyrrolidone, N,N-dimethylaminoethyl methacrylate, ethylene, propylene, vinyl chloride, vinyl fluoride, vinylidene fluoride, hexafiuoropropylene, chlorotritluoroethylene, and tetrafiuoroethylene may also be used as the monomers for making the main polymer. Co-polymers of the various monomers just mentioned may be prepared by the polymerization system of the present invention and copolymers of any one or more of the above-mentioned monomers with up to 50% by weight of maleic anhydride may be formed by the system of the present invention.

To illustrate the need for consideration of the particu: lar monomer in selecting the hydrocarbon medium, when the polymer is formed largely of styrene, the hydrocarbon selected should be of acyclic aliphatic character in which the polymer is insoluble since hydrocarbon media having a large aromatic component would dissolve the polymer.

In the polymerization system of the present invention, several variations in procedure may be employed. The most readily adaptable system which is also highly convenient to use is that of free-radical type polymerization. This type of polymerization employs a free-radical catalyst of azo or peroxygen type. Examples include benzoyl peroxide, lauroyl peroxide, a-cetyl peroxide cumene hydroperoxide, paramenthane hydroperoxide, azodiiso'butyronitrile, dimethyl azodiisobutyrate, and so on. Any of the free-radical type catalysts which are soluble in the monomer or the hydrocarbon may be employed. Free-radical catalysts which are activated by means of amines such as triethylenetetramine and those activated by various salts such as cobalt naphthenate are suitable. In general, any free-radical catalyst that can be used -for bulk or solution polymerization of the monomers herein enumerated can be employed in the present invention. The proportion of catalyst may be from 0.1% to 3% of the weight of monomer or monomers. The amount employed may depend on the method of addition and the molecular weight desired in the dispersed polymer. Of course, the catalyst may be added all at once or in portions at periodic intervals.

A. FREE RADICAL SYSTEM WITH PRELIMINARY PRECURSOR ACTIVATION STEP The simplest procedure involving the free-radical type of polymerization is to dissolve the dispersing agent pre cursor in the liquid hydrocarbon which is to serve as the medium of polymerization. The proportion of the precursor may be from about 2 to 20% of the weight of polymer to be dispersed by the dispersing agent. In fact, the proportion of dispersing agent may even be much higher such as up to 30% or more in the systems of the present invention since the dispersing agent is of water-insensitive character and films or coatings obtained from the polymer dispersions prepared therewith are not susceptible to deterioration or disintegration bymoisture or high humidity. To the solution of the precursor in the hydrocarbon medium, the catalyst or initiator is added. The proportion of initiator may be from 0.1 to 5% by weight of the precursor. After addition of the initiator to the solution of precursor, the mixture is heated to temperatures of 65 to 120 C. or more (keeping below the decomposition temperature of the precursor. The time for this preliminary heating may vary depending upon the particular precursor, the time being longer at lower temperatures and shorter at the higher temperatures. For example, the time may vary from 5 minutes up to an hour or more. When the precursor is of a character which is capable of cross-linking on heating, the temperature should be kept below the temperature which would effect cross-linking.

After active sites are formed on the precursor in this manner, the monomer or monomers to be polymerized to form the main polymer are introduced along with additional catalyst if needed. The mixture is heated with continued agitation to a suitable polymerization temperature which depends upon the particular initiator and the particular monomer. In some cases instead of heating, the system may simply be allowed to react at room temperature or it may be cooled particularly when an activated peroxide initiator is used. With such activated catalysts, temperatures of -5 to C. may be employed. In other systems, the temperatures may be raised to as much as 50 C. or as high as 120 C. or higher depending upon the vapor pressure of the hydrocarbons and monomers and available pressure equipment to avoid loss by volatilization. Generally, the temperature is controlled to avoid too rapid a polymerization and to avoid such a high temperature as to preclude the grafting of a portion of the monomer upon the dispersing agent. In general, the polymerization is carried to as high a conversion as is practical in a suitable period of time. As much as 94 to.98% conversion can be obtained in a period of onehalf to 48 hours depending upon the particular monomers and initiators and proportions. For most practical operations, 2 to 10 hours may be employed. The proportion of monomers added to the precursor solution may vary over a wide range so as to provide a main polymer concentration from about 1% to about 55% or more in the polymer dispersion prepared.

After completion of the polymerization, the final concentration of the polymer dispersion may be varied by dilution with additional liquid hydrocarbon or by the removal, such as by distillation, of a portion of the hydrocarbon medium during which a portion or all of any residual monomer may also be removed. In this manner polymer dispersions containing as low as 1% concentration or less or as high as 50 to 65% may be obtained. For most purposes, concentrations of 10 to 45% of dispersed polymer (excluding dispersing agent) are generally employed.

B. FREE-RADICAL SYSTEM WITHOUT PRELIML NARY PRECURSOR ACTIVATION STEP A variation of the procedure just described involves the dissolution of the polymeric precursor, the monomer to be polymerized to form the main polymer, and the free-radical initiator in the hydrocarbon medium. After preparing this mixture, it may be heated (or cooled) with agitation under conditions generally consistent with those suggested in the preceding description to effect polymerization. The proportion of initiator may be from 0.01 to 5% by weight of the total weight of monomer and precursor and the concentration of monomer may be such as to result in a main polymer concentration of 1 to 60% or more.

In either of the two procedures of preparing the polymer dispersions just described (under headings A and B), there may be present an excess of the precursor over that which is copolymerized with a portion of the monomer by grafting so that in effect, the resulting polymer dis- 6 persion also contains an amount of precursor which is not modified by grafting with the added monomer. The result is a blended polymer composition of its own distinctive character. This is particularly advantageous in the preparation of a pigmented polymer dispersion intended to be employed as a paint, wherein the precursor employed is an oxidized linseed oil. As much as 50 to of the precursor may thus be unmodified by grafting and form a substantial component in the final polymeric system.

C. FREE-RADICAL PRELIMINARY FORMATION OF DISPERSING AGENT Another modification involves the heating of the solution of the precursor containing the free-radical initiator as in the first procedure (A) described, but adding only a limited proportion of the monomer-as the second step after the formation of active sites on the precursor. Thus, only 10 to by weight, based on the weight of the precursor, of the monomer or monomer mixture is added. At this point, the system is heated with continued agitation to effect copolymerization and grafting of the monomer or monomers on the precursor. After substantial grafting has been effected, the remainder of the monomer is added and polymerization is continued as before to form the main polymer. In this case, if an activated peroxide is employed as initiator, the polymerization in both the grafting and final polymerization stages may be effected at low temperatures of -5 to 10 C. as before.

D. CATIONIC SYSTEMS Instead of employing a free-radical system, a cationic polymerization system or technique may be employed. This uses the conventional Friedel-Crafts or acidic catalysts such as aluminum chloride, stannic chloride, boron fluoride and its complexes such as the etherates, titanium tetrachloride, aluminum bromide, sulfuric acid, and certain activated clays. The proportion of catalyst em ployed in this system may be from 0.1 to 1% on the monomer in the final dispersion prepared. In this system, the precursor may first be introduced into the hydrocarbon medium with the Friedel-Crafts catalyst, the monomers are introduced into the solution, and the polymerization is carried out to form a polymer from the monomer. This system is particularly adapted to the polymerization of the lower alkyl vinyl ethers such as the methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and t-butyl vinyl ethers, flt-mfithyl styrene, and alkoxy-a-methyl styrenes, such as paramethoxy-a-methyl styrene, and other monomers having an electron donor group on the double bond.

The cationic system may be varied by introducing into the hydrocarbon medium not only the acidic catalyst but also the monomers and a grafted precursor such as that prepared with a free-radicalinitiator and l0 to 150% of the monomer on the precursor as described hereinabove in procedure C. Ingeneral, this is the preferred manner of preparing a polymer dispersion when using a cationic polymerization system for forming the main polymer dispersed therein.

E. ANIONIC SYSTEMSY The same procedures as described hereinabove (A,'B, and C) for making the polymer dispersions by a freeradical type of polymerization may be employed with an anionic technique. In this technique, the catalysts are of anionic type including such materials as butyllithium, butylmagnesium bromide, phenylmagnesium bromide, triphenylmethylsodium, sodium naphthalene, 9-fluorenyllithium, and dipotassium stilbene. The proportion of this catalyst is from 0.1 to 5% on the weight of the monomers. This system is particularly adapted to the polymerization of such monomers as vinylidene cyanide, esters of a-cyano acrylic acid, a-trifluoro methylacrylonitrile, N,N-dialkyl-substituted acrylamides and -methacrylamides, itaconic acid esters, acrylic acid esters and methacrylic acid esters, acrylonitrile, methacrylonitrile, and ethylene, particularly using the anionic Ziegler catalysts. The anionic system may also be employed only for the polymerization of the main polymer in which event the precursor graft or dispersing agent may be prepared by the free-radical system using to 150% of the monomer on the precursor as above in procedure C and the main polymer then prepared in a dispersion of the monomer or monomers with the dispersing agent and the anionic catalyst in the hydrocarbon medium.

As pointed out hereinabove, the products are dispersions in liquid hydrocarbon media containing discrete particles of the main polymer dispersed by a polymeric dispersing agent. Generally, the polymer dispersions of the present invention may have concentrations varying from 1 to 55% or higher solids. These compositions, as pointed out hereinabove, are dilutable by the addition of a suitable liquid hydrocarbon mentioned hereinabove to any desired concentration for application for the coating and impregnation of various substrates as Well as for the formation of free films by casting techniques. Thus, the polymer dispersions may be employed for the impregnation and coating of textile fabrics, paper, paperboards, leathers, wood, metals, ceramics, concrete, bricks, stones, plaster, vinyl wall tile and flooring tile, linoleum, asphalt tile, and asbestos cement products including siding and shingles. As pointed out hereinabove, the coatings and impregnations thereby obtained are insensitive to water by virtue of the fact that there is present no hydrophilic emulsifier or dispersing agent. The viscosity of the dispersion is adapted to be easily controlled merely by the addition of a solvent or swelling agent simply by adding a hydrocarbon which has no solvent or swelling action on the dispersed polymer.

The polymer dispersions of the present invention are adapted to be modified by the incorporation of drying oils, pigments, fillers, dyes, as well as plasticizers, and polymeric or resinous materials which are soluble in the hydrocarbon liquid vehicle including fatty acid-modified shellac, gums, natural resins, epoxidized fatty oils, coal tar, cumarone-indene resins, asphalts, bitumens, epoxy resins organic-soluble alkylated methylolated s aminoplast resins including the condensates of formaldehyde with urea, melamine, thiourea, benzoguanamine, ethyleneurea, alkylated with an alcohol having 2 to 6 carbon atoms such as n-butanol. Among other materials that can be incorporated are the alkyds, organic solvent-soluble vinyl and acrylic resins with or without plasticizers including plastisols obtained from polyvinyl chloride, or copolymers of vinyl chloride and plasticizers therefor.

In the following examples which are illustrative of the invention, the parts and percentages are by weight unless otherwise noted.

Example 1 Ten parts of a coploymer of about 10% of N-vinyl-Z- pyrrolidone, about 30% of butyl acrylate, about 35% of lauryl methacrylate, and about 25% of stearyl methacrylate in parts of toluene and 0.2 part of benzoyl peroxide were added to 185 parts of a commercial octane. The mixture was stirred and heated to 95 to 107 C. for 45 minutes. A mixture of 45 parts of methyl methacrylate and 45 parts of ethyl acrylate was added and the mixture was refluxed for two hours. A stable polymeric dispersion resulted. It contained about 30% solids consisting essentially of 87% of a main copolymer of methyl methacrylate and ethyl acrylate (about 50:50 weight ratio) dispersed as undissolved particles having a range of sizes from about 0.2 to 1.8 microns and about 13% of a dissolved polymeric dispersing agent formed of a graft of methyl methacrylate and ethyl acrylate in approximately equal amounts on the N-vinylpyrrolidone copolymer. The dispersion was applied as a base-coat to handbuff and full-grain leathers.

8 Example 2 Ten parts of poly(isobornyl methacrylate) was dissolved in 160 parts of commercial octane and 0.2 part of benzoyl peroxide was added. The mixture was heated to 99 to 100 C. for one-half hour. Fifteen parts of methyl methacrylate and 60 parts of ethyl acrylate were added. The resulting solution was stirred and heated at 99 to 100 C. for four hours under an atmosphere of nitrogen. A viscous, white dispersion was formed. Its solids content was about 51% made up of about 85% of a dispersed main copolymer of about 80% methyl methacrylate and 20% ethyl acrylate having particle sizes in the range of about 0.3 to 2.5 microns and about 15% of a dissolved graft copolymer of methyl methacrylate and ethyl acrylate on the poly(isobornyl methacrylate). A hard, glossy, moisture-resistant finish is produced on vinyl and linoleum Wall tile by coating the tile with the dispersion of the methyl methacrylate/ ethyl acrylate copolymer at room temperature and then airdrying.

Example 3 Air was bubbled through 500 parts of refined linseed oil heated at 120 C. with vigorous stirring for two hours. The temperature was raised to 127 to 136 C. for an additional five hours. The Gardner-Holdt viscosity of the oil rose from A to 25-3. Five parts of this oxidized oil was dissolved in parts of commercial octane. To this solution 22.5 parts of methyl methacrylate and 22.5 parts of ethyl acrylate were added and the mixture was stirred and heated at reflux temperature for four hours. The milky latex obtained had a solids content of about 38% consisting essentially of 85% of a 50:50 copolymer of methyl methacrylate and ethyl acrylate in the form of undissolved particles ranging in size from about 0.1 to 9.5 microns and 15% of dissolved graft copolymer of the methyl methacrylate and ethyl acrylate on the oxidized linseed oil. A mixture of 5 parts butoxyethyl acetate and 5 parts of commercial octane was added to the polymer dispersion which was then formed into a continuous selfsupporting film of water-resistant and grease-resistant character by coating plates of glass and stripping the dried coatings therefrom.

Example 4 A mixture of 10 parts of lauryl methacrylate, 0.1 part of benzoyl peroxide, and 75 parts of a commercial heptane was stirred and heated to reflux temperature under an atmosphere of nitrogen. Refiuxing was continued for one hour and 40 parts of methyl methacrylate was added. Refiuxing was continued for 5 hours to give a white polymer dispersion. Its solids content was about 37%. The main polymer, a homopolymer of methyl methacrylate, had a range of particle sizes from about 0.3 to 3.1 microns and it amounted to about of the solids content, the remainder being the dissolved dispersing agent, a graft copolymer of methyl methacrylate about 15% on the poly(lauryl methacrylate) Hard, continuous films are obtained from the dispersion by casting and drying at temperatures of 80 to C.

Example 5 Repeat the procedure of Example 1 except for the replacement of the mixture of 45 parts of methyl methacrylate and 45 parts of ethyl acrylate with a mixture of 20 parts of methyl methacrylate, 30 parts of vinyltoluene, 33 parts of ethyl acrylate, 10 parts of n-butyl acrylate, and 2 parts of methacrylic acid. The resulting milky dispersion after dilution to spraying viscosity was applied to cold rolled steel by spraying and dried at C.

Example 6 Repeat the procedure of Example 4 except for the replacement of the methyl methacrylate (40 parts) with a mixture of 5 parts of methyl methacrylate, 20 parts of vinylidene chloride, and 15 parts of ethyl acrylate. The

. 9' composition contained the dispersed copolymer of methyl methacrylate, vinylidene chloride, and ethyl acrylate (approximately :20: weight ratio) dispersed in a range of particle sizes from 0.4 to 2.7 microns by a dissolved graft copolymer of the several monomers added on the oxidized linseed oil.

Example 7 Repeat the procedure of Example 4 except substitute 10 parts of n-hexyl methacrylate for the lauryl methacrylate, replace the parts of methyl methacrylate with 33 parts of methyl methacrylate and 67 parts of ethyl acrylate, and replace the heptane with octane. A low viscosity milky latex-like dispersion was obtained.

Example 8 To a solution of 10 parts of oxidized linseed oil (prepared as in Example 3) in 150 parts of commercial heptane there was added 80 parts of methyl methacrylate, 10 parts of acrylic anhydride and 0.4 part of lauroyl peroxide. The mixture was stirred and heated at reflux temperature for four hours. The dispersion had a solids content of about 37%. The undissolved methyl methacrylate/ acrylic anhydride copolymer had particle sizes ranging from 0.3 to 3.5 microns. A mixture of 5 parts of butoxyethyl acetate and 5 parts of commercial octane was added to the polymer dispersion which was then formed into a continuous self-supporting film of water-resistant and grease-resistant character by coating plates of glass and stripping the dried coatings therefrom.

Example 9 A solution was prepared containing 10% of an oilsoluble copolymer of n-butyl methacrylate and 40% of tert-octyl methacrylate in mineral spirits (a volatile petroleum product intermediate between gasoline and kerosene which is used extensively as a thinner for paints and varnishes and falls within the scope of ASTM designation D235-39 (ASTM Standards (1958) page 137)). 40 grams of this solution was mixed with 111 grams of mineral spirits and 0.1 gram of lauroyl peroxide was added to the mixture in a suitable reaction vessel. The atmosphere in the vessel was swept with nitrogen and the reaction mixture was heated to 89 C. with agitation for one hour to introduce active sites into the copolymer. It was then cooled to 30 C. Then 0.2 gram of benzoyl peroxide was dissolved in a mixture of 10 grams of methyl methacrylate, 23 grams of acrylonitrile, grams of, ethyl acrylate, and 2 grams of maleic anhydride, and the resulting mixture was added all at once to the first mixture. The mixture obtained thereby was heated at reflux (79 C.). After the elapse of about one and one-half hours, a definite cloudiness showing the formation of polymer became evident. The heating of the mixture was continued at reflux for another 3 hours, whereupon an addi tional 0.2 gram of lauroyl peroxide dissolvedin 2 grams of mineral spirits was added. After continued heating at reflux for another three hours, another addition of 4 gram of lauroyl peroxide in 2 grams of mineral spirits was made and heatingwas continued at reflux for another three hours at which time another addition of 0.2 gram of lauroyl peroxide in 2 grams of mineral spirits was made and heating was continued at reflux for another six hours. During all of the heating, the atmosphere in the vessel was swept with nitrogen and the reaction mixture was continuously agitated. The product amounted to a total of 251.3 grams of a polymer dispersion having 37.3% solids in which there was effected a 92.4% conversion of the monomer into the polymer. The dispersion was homogeneous to all appearances having a slightly yellowish milky appearance. The particle size of the undissolved copolymer of methyl methacrylate, ethyl acrylate and maleic anhydride ranged from about 0.1 to 1.9 microns. This dispersed polymer constituted about 94% of the solids, being dispersed by a graft copolymer of the several monomers on the initial oil-soluble copolymer.

. 10 No solid matter was left on a filter after filtering. Casting of the dispersion upon glass and metal plates produced clear films which were soft and tough and quite hydrophobic. The coating adhered well to metal, but was separable from the glass as an integral film if dried under normal drying conditions up to about 100 C. However the adhesion to glass was greatly improved by baking the coated glass plates for about 30 minutes at 150 C.

We claim:

1. A composition of matter comprising a substantially anhydrous dispersion, in a liquid essentially inert hydrocarbon medium having aboiling range from about -50 C. to 300 C. and consisting essentially of at least one member selected from the group consisting of aliphatic, aromatic, and naphthenic hydrocarbons, of an essentially linear addition polymer of ethylenically unsaturated mole cules which is essentially insoluble in the medium, not over 10% by weight of the dispersed polymer being dissolved in the medium and to by weight of the dispersed polymer being in the form of discrete particles having a. size of about 0.1 to 10 microns dispersed in the medium by a hydrophobic polymeric dispersing agent comprising a component of polymeric size formed of a polymeric precursor which is soluble in the medium and a component formed of polymerized monomer molecules of essentially similar constitution to that of polymerized monomer molecules in the dispersed addition polymer to render this latter component preferentially soluble in the dispersed polymer, the precursor being a hydrocarbonsoluble polymer containing suflicient hydrocarbon groups of at least four carbon atoms to impart solubility thereof in the hydrocarbon medium selected from the group consisting of homopolymers and copolymers of at least one ester of an acid of the formula Where n is an integer having a value of 1 to 2 with an alcohol having from 4 to 18 carbon atoms.

2. A composition of matter comprising a substantially anhydrous dispersion, in a liquid essentially inert hydrocarbon medium having a boiling range from about 50 C. to 300 C. and consisting essentially of at least one member selected from the group consisting of aliphatic, aromatic, and naphthenic hydrocarbons, of an essentially linear addition polymer of ethylenically unsaturated molecules which is essentially insoluble in the medium, not over 10% by weight of the dispersed polymer being dissolved in the medium and 90% to 100% by weight of the dispersed polymer being in the form of discrete particles having a size of about 0.1 to 10 microns dispersed in the medium by a hydrophobic polymeric dispersing agent comprising a component of polymeric size formed of a polymeric precursor which is soluble in the medium and a component formed of polymerized monomer molecules of essentially similar constitution to that of polymerized monomer molecules in the dispersed addition polymer to render this latter component preferentially soluble in the dispersed polymer, the precursor being a hydrocarbon soluble polymer containing sufiicient hydrocarbon groups of at least four carbon atoms to impart solubility thereof in the hydrocarbon medium selected from the group consisting of homopolymers and 'copolymers of at least one ester of an acid of the formula wherein n is an integer having having a value of 1 to 2 with an alcohol having from 4 to 18 carbon atoms, and said ethylenically unsaturated molecules being selected from the group consisting of vinyl esters of a fatty acid having 1 to 18 carbon atoms, esters of acrylic acid with an alcohol having 1 to 18 carbon atoms, esters of methacrylic acid with an alcohol having 1 to 18 carbon atoms, phenyl acrylate, phenyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, "methacrylamide, styrene, methyl styrene, vinyl toluenes, acrylic acid, acrylic acid anhydride, methacrylic acid, methacrylic acid anhydride, maleic anhydride fumaric acid, crotonic acid, allyl acetate, glycidyl methacrylate, t-butylaminoethyl methacrylate, hydroxyalkyl acrylates, hydroxyalkyl methacrylates, fi-hydroxyethyl vinyl ether, fi-hydroxyethyl vinyl sulfide, vinyl pyrrolidone, N,N-dimethylaminoethyl methacrylate, ethylene, propylene, vinyl chloride, vinyl fluoride, vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, tetrafluoroethylene, lower alkyl vinyl ethers in which the alkyl group has 1 to 4 carbon atoms, p-methoXy-a-methylstyrene, vinylidene cyanide, esters of a-cyano-acrylic acid, a trifluoromethyl-acrylonitrile, N,N-dialkylacrylamides, N,N-dialkylmethacrylarnides,.and itaconic acid esters.

3. vA composition of matter comprising a substantially anhydrous dispersion, in a liquid essentially inert hydrocarbon medium having a boiling range from about -50 C. to 300 C. and consisting essentially of at least one member selected from the, group consisting of aliphatic, aromatic, and naphthenic hydrocarbons, of a linear polymer of an ester of an acid of the formula wherein n is an integer having a value of 1 to 2 with an alcohol having 1 to 18 carbon atoms which is essentiallyinsoluble in the medium, not over by weight of the dispersed polymer being dissolved in the medium and 90% to 100% by weight of the dispersed polymer being in the form of discrete particles having a size of about 0.1 to 10 microns dispersed in the medium by a hydrophobic polymeric dispersing agent comprising a component of polymeric size formed of a hydrocarbon-soluble polymer containing sufiicient hydrocarbon groups of at least four carbon atoms to impart solubility thereof in the hydrocarbon medium selected from the group consisting of homopolymers and copolymers of at least one ester of an acid of the formula Hz z)n-iH wherein nis an integer having a value of 1 to 2, and a component of polymeric size formed of polymerized monomer molecules of essentially similar constitution to that of the polymerized ester molecules in the dispersed polymer to render this latter component preferentially soluble in the dispersed polymer.

References Cited by the Examiner UNITED STATES PATENTS 2,556,336 6/1951 Nye 26023 2,926,153 2/1960 Christenson 26023 3,095,388 6/1963 Osmond et al 260-336 FOREIGN PATENTS 1,196,416 11/1959 France.

LEON I. BERCOVITZ, Primary Examiner.

M. STERMAN, Examiner. 

1. A COMPOSITION OF MATTER COMPRISING A SUBSTANTIALLY ANHYDROUS DISPERSION, IN A LIQUID ESSENTIALLY INERT HYDROCARBON MEDIUMHAVING A BOILING RANGE FROM ABOUT -50* C. TO 300*C. AND CONSISTING ESSENTIALLY OF AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC, AROMATIC, AND NAPHTHENIC HYDROCARBONS, OF AN ESSENTIALLY LINEAR ADDITION POLYMER OF ETHYLENICALLY UNSATURATED MOLECULES WHICH IS ESSENTIALLY INSOLUBLE IN THE MEDIUM, NOT OVER 10% BY WEIGHT OF THE DISPERSED POLYMER BEING DISSOLVED IN THE MEDIUM AND 90% TO 100% BY WEIGHT OF THE DISPERSED POLYMER BEING IN THE FORM OF DISCRETE PARTICLES HAVING A SIZE OF ABOUT 0.1 TO 10 MICRONS DISPERSED IN THE MEDIUM BY A HYDROPHOBIC POLYMERIC DISERSING AGENT COMPRISING A COMPONENT OF POLYMERIC SIZE FORMED OF A POLYMERIC PRECUSOR WHICH IS SOLUBLE IN THE MEDIUM AND A COMPONENT FORMED OF POLYMERIZED MONOMER MOLECULES OF ESSENTIALLY SIMILAR CONSTITUTION TO THAT OF POLYMERIZED MONOMER MOLECULES IN THE DISPERSED ADDITION POLYMER TO RENDER THIS LATTER COMPONENT PREFERENTIALLY SOLUBLE IN THE DISPERSED POLYMER, THE PRECURSOR BEING A HYDROCARBONSOLUBLE POLYMER CONTAINING SUFFICIENT HYDROCARBON GROUPS OF AT LEAST FOUR CARBON ATOMS TO IMPART SOLUBILITY THEREOF IN THE HYDROCARBON MEDIUM SELECTED FROM THE GROUP CONSISTING OF HOMOPOLYMERS AND COPOLYMERS OF AT LEAST ONE ESTER OF AN ACID OF THE FORMULA CH2=C(-COOH)-(CH2)(N-1)-H WHERE N IS AN INTEGER HAVING A VALUE OF 1 TO 2 WITH AN ALCOHOL HAVING FROM 4 TO 18 CARBON ATOMS. 